1. Field of Invention
This invention relates to catalytic reaction apparatus such as for producing product gases from a feedstock.
2. Description of Prior Art
Catalytic reaction apparatus, such as for converting hydrocarbon feedstocks to useful industrial gases, for example hydrogen, is well known in the art. In this regard, commercial production of hydrogen from hydrocarbon feedstocks is most commonly achieved by passing a mixture of steam and hydrocarbon through catalyst filled reactor tubes vertically supported within a furnace chamber.
In commercial steam reformers endothermic heat is commonly supplied by the combustion of fuel and oxidant in a diffusion flame burner which radiates heat to the refractory furnace walls, heating them to incandescence, and thereby providing a radiant source for heat transfer to the reactor tubes. Uniform radiation to the reactor tubes is critical since excessive local heating of a reactor tube wall will result in diminished life expectancy for the reactor apparatus.
Portions of the reactor tube which are in direct line of sight with the burner flame, which are impinged by the burner flame, or which are too closely spaced to the radiating refractory, will become hotter than the remaining portions.
In large-scale commercial steam reformers, maldistribution of heat within the furnace chamber is minimized by providing large spacing between individual reactor tubes, the furnace walls, and the burner flames. However, for small scale catalytic reaction apparatus which is uniquely compact, special design features must be employed.
In the prior art U.S. Pat. No. 4,098,587 to Kral el al, there is described a compact reformer comprising a plurality of reactor tubes disposed within the combustion volume of a furnace. Baffles, such as sleeves, are disposed around portions of the reactor tubes to shield the tubes from excessive radiant heat from the walls of the furnace and to more evenly distribute heat among and around all of the reactors. It is therein described that the use of such baffles allows close spacing between reactor tubes while simultaneously avoiding excessive local heating of reactor tube walls. In the present invention, uniform radiant heat distribution to the reactor tube walls is achieved through the use of an annular reaction chamber concentrically disposed around an internal burner chamber containing a uniformly radiating infrared burner. This configuration is in contradiction to the prior art U.S. Pat. No. 4,098,587 which teaches the use of reactor tubes disposed within a furnace volume and surrounded by baffles.
The catalytic reaction apparatus as embodied in the present inenvtion achieves the objects of compact design and long life expectancy by application of a novel burner chamber configuration which prevents flame impingement or direct line-of-sight between burner flame and reaction chamber, and which provides a means for uniformly distributing heat along the axial and circumferential dimensions of the reactor.